Method of fabricating a non-hollow fiber having a regular polygonal cross-section

ABSTRACT

Fibers or filaments made by using a spinneret orifice having a regular polygonal cross-section. Melt-spinnable thermoplastic polymer is melted and extruded through a spinneret orifice having a regular polygonal cross-section to form molten filaments. The molten filaments are then solidified, and optionally are subsequently subjected to stretching and false twisting processes.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method of fabricating a non-hollow fiber having a regular polygonal cross-section. In particular, the present invention relates to a method of fabricating a non-hollow fiber having a regular rectangular or regular triangular cross-section. The present invention also relates to a fabric manufactured by the fibers, which demonstrates good windproof characteristic and brightness.

[0003] 2. Description of the Related Art

[0004] Many efforts have been made to improve the characteristics of synthetic filaments or fibers so as to provide fabrics or textiles having good performances and functions, such as moisture-absorbing properties, sweat-expelling properties, antistatic properties, sustained release characteristics, antibacterial properties, thermal insulation, windproof characteristics and brightness.

[0005] U.S. Pat. No. 5,057,368 issued to Largman et al, discloses trilobal or quardrilobal filaments useful in such diverse applications such as filtering, wicking, insulating and other applications.

[0006] U.S. Pat. No. 5,279,879 issued to Goodall et al, discloses hollow synthetic filaments having a four sided cross-section and four substantially equispaced continuous voids. The filaments are especially suitable for making carpets which demonstrate improved soil-resistance.

[0007] Fabrics or textiles in which the filaments or yarns are woven in a dense structure are suitable for manufacturing clothes that require good windproof characteristics. Such clothes are conventionally made of ultra-fine filaments. The need for ultra-fine filaments inevitably increases the cost of the clothes.

SUMMARY OF THE INVENTION

[0008] An object of the present invention is therefore to provide fabrics or textiles that demonstrate superior windproof characteristics, and can be made at a lower cost.

[0009] To attain the object, the invention provides non-hollow fibers or filaments having regular polygonal cross-section. As the fibers or filaments are solid and have equilateral sides in cross-section, the fibers or filaments can be arranged in a denser manner when woven, and thus the resulting fabrics or clothes have superior windproof characteristics.

[0010] According to another aspect of the inventions as there is no need to use ultra-fine filaments, the production cost of manufacturing windproof clothes is significantly reduced.

[0011] According to a further aspect of the invention, as the filaments or yearns can be woven in a more dense manner, the heat insulating properties and the brightness of the woven fabrics or textiles are also significantly improved.

[0012] The fibers or filaments of the present invention are made by using a spinneret orifice having a regular polygonal cross-section.

[0013] Specifically, the fibers or filaments of the invention are made by melting a thermoplastic polymer; extruding the melted polymer through a spinneret orifice having a regular polygonal cross-section to form molten filaments; and solidifying the molten filaments. Usually, the solidified filaments are subsequently subjected to stretching and false twisting processes.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention can be more fully understood by reading the subsequent detailed description in conjunction with the examples and references made to the accompanying drawing, wherein:

[0015]FIG. 1 is a photo showing the cross-section of the non-hollow rectangular cross-sectional filaments made in example 1; and

[0016]FIG. 2 is a photo showing the cross-section of the non-hollow triangular cross-sectional filaments made in example 3.

DETAILED DESCRIPTION OF THE INVENTION

[0017] The fibers or filaments of the invention are non-hollow fibers and filaments having regular polygonal cross-section. The preferred filaments of the invention are those that have regular rectangular or regular triangular cross-section, although the invention is not limited to the preferred filaments.

[0018] The term “regular polygonal” indicates that each side of the polygon has equal length, that is, is a regular polygonal.

[0019] The filaments are prepared by spinning molten polymer through spinneret capillaries or orifices designed to provide the desired configuration of the cross-section of the filaments. That is, the orifices are designed and formed in a configuration having a corresponding regular polygonal cross-section.

[0020] The filaments may be prepared from synthetic thermoplastic polymers melt-spinnable. Examples of these polymers include but are not limited to polyester, polyamide and polyolefin.

[0021] Polyesters that are suitable for use in this invention are those derived from the condensation f aromatic and cycloaliphatic dicarboxylic acids and may be cycloaliphatic, aliphatic or aromatic polyesters. Examples or these polyesters are poly(ethylene terephthalate), poly(cyclohexylenedimethylene terephthalate), poly(lactide), poly(butylenes terephthalate), poly(glycolic acid) and poly(ethylene adipate). Among these, poly(ethylene terephthalate) is preferred. Other examples of suitable polyesters are those mentioned in U.S. Pat. Nos. 4,454,196, 4,410,073 and 4,359,557 incorporated herein for references.

[0022] Polyamides of the above description are well known in this art and include, for example nylon 6 (poly(6-aminohexanoic acid)), nylon 66 (poly(hexamethyleneadipamide)), nylon 4 (poly(4-aminobutyric acid)), nylon 11 (poly(11-amino-undecanoic acid) and the like. The preferred polyamides are nylon 6 and nylon 66. Other examples of suitable polyamides can be seen from “Textile fiber handbook”, 5^(th) edition, Trowbridge GB (1984), pp 19-20.

[0023] Examples of polyolefin that can be used in this invention as raw material include, but are not limited to polyethylene, polypropylene, polyisobutene, poly(4-methyl-1-pentene), poly(3-methyl-1-butene), and poly(1-hexene). Among these polyolefins, polypropylene is preferred. Other examples of useful polyolefins can be found from U.S. Pat. Nos. 4,137,391, 4,562,869, 4,567,092 and 4,559,862 included herein for reference. Also, a blend of the above-mentioned polymers is also suitable for use according to the present invention.

[0024] The manufacturing method of the fibers or filaments of the invention are substantially the same as conventional melt spinning techniques except that a spinneret orifice having a configuration sufficient to provide a fiber having regular polygonal cross-section is used. The raw material, ie., the plastic polymers is melted and is extruded through the spinneret to form molten filaments. The melting temperature is usually between 150-300° C. depending on the melting point of the polymer used and the type of the spinneret selected. For example, if polyethylene terephthalate is used as raw material, it is heated to 270-300° C. to melt, and if polypropylene is used, the melting temperature is preferably between 200-280° C.

[0025] In the melt spinning process, the molten polymer is extruded into air or other gas, or into a suitable liquid to cool and solidify the molten filaments. Usually, the solidifying process is conducted by using quenching gases, for example chilled air, at a temperature of about 10-25° C. The temperature and the velocity of the quenching air blown to the molten filaments may vary depending on the polymer used and the desired properties of the filament. Usually, the filaments are also lubricated with oil at about 100-120 cm from the orifice of the spinneret so as to facilitate the solidifying process. The oil amount (OPU, oil per unit) used is about 0.5-0.8% and may vary depending on the polymer used and other spinning conditions. Before being taken up, the filaments may be subjected to further processing such as stretching and false twisting to increase their bulk. Note that in the stretching and false twisting process, it is important to maintain the regular polygonal cross-section of the filaments. This can usually be attained by properly adjusting the machine used for performing these operations.

[0026] The fibers or filaments produced by the above process have a solid and regular polygonal cross-section and have a fineness of 0.5-5 dpf (denier per filament). The fibers of the invention can be employed in many applications, and are not limited to the fabrication of woven, non-woven, and knitted fabrics or clothes. The fibers of the invention are particularly suited for use in the fabrication of fabrics or textiles that require superior wind proofing, brightness and heat insulation.

[0027] The following examples are presented to further illustrate the invention and are not to be construed as limitations thereon.

EXAMPLE 1 The Preparation of Fibers Having Regular Rectangular Cross-Section (1)

[0028] A melt dope containing R-PET (intrinsic viscosity=0.64, Shinkong Synthetic Fibers Corporation) was prepared by melting the polymer at 280° C. The melt was then spun at 32.8 grams/minute through a spinneret having regular rectangular orifice. The filaments extruded from the orifice were then cooled by blowing with a quenching air of 16.1° C. at 0.44 meter/sec. velocity. After quenching, the filaments were treated with an aqueous liquid containing 10% oil by contacting an applicator located at a distance of 110 cm from the orifice so as to facilitate the solidifying of the hot filaments. The oil per unit of the treatment was 0.6%. The cooled and solidified filaments were then taken up by passing through a pair of driven take-up rolls at a speed of 3000 meter/minute. The obtained yarn bundles are 100 denier, and 24 filaments per yarn bundle. The strength (gram/denier) and the elongation (%) of the yarn bundles were first tested. The yarn bundles were then subjected to stretching and false twisting, and tested for their strength and elongation. The results are summarized in Table 1 below. The cross-section of the resulting fiber is shown in FIG. 1.

EXAMPLE 2 The Preparation of Fibers Having Regular Rectangular Cross-Section (1)

[0029] A melt dope containing PET (intrinsic viscosity=0.64) was prepared by melting the polymer at 280° C. The melt was then spun at 65.6 grams/minute through a spinneret having regular rectangular orifice. The filaments extruded from the orifice were then cooled by blowing with a quenching gas of 16.1° C. at 0.44 meter/sec. velocity. After quenching, the filaments were treated with an aqueous liquid containing 10% oil by contacting an applicator located at a distance of 110 cm from the orifice so as to facilitate the solidifying of the hot filaments. The oil per unit of the treatment was 0.6%. The cooled and solidified filaments were then taken up by passing through a pair of driven take-up rolls at a speed of 3000 meter/minute. The obtained yarn bundles are 200 denier, and 24 filaments per yarn bundle. The strength (gram/denier) and the elongation (%) of the yarn bundles were first tested. The yarn bundles were then subjected to stretching and false twisting, and tested for their strength and elongation. The results are summarized in Table 1 below. The cross-section of the resulting fiber is shown in FIG. 1.

COMPARATIVE EXAMPLE 1 The Preparation of Fibers Having Round Cross-Section (1)

[0030] A melt dope containing R-PET (intrinsic viscosity=0.64) was prepared by melting the polymer at 280° C. The melt was then spun at 31.8 grams/minute through a spinneret having round orifice. The filaments extruded from the orifice were then cooled by blowing with a quenching gas of 16.1° C. at 0.44 meter/sec. velocity. After quenching, the filaments were treated with an aqueous liquid containing 10% oil by contacting an applicator located at a distance of 110 cm from the orifice so as to facilitate the solidifying of the hot filaments. The oil per unit of the treatment was 0.6%. The cooled and solidified filaments were then taken up by passing through a pair of driven take-up rolls at a speed of 3000 meter/minute. The obtained yarn bundles are 100 denier, and 24 filaments per yarn bundle. The strength (gram/denier) and the elongation (%) of the yarn bundles were first tested. The yarn bundles were then subjected to stretching and false twisting, and tested for their strength and elongation. The results are summarized in Table 1 below.

COMPARATIVE EXAMPLE 2 The Preparation of Fibers Having Round Cross-Section (2)

[0031] A melt dope containing R-PET (intrinsic viscosity=0.64) was prepared by melting the polymer at 280° C. The melt was then spun at 65.1 grams/minute through a spinneret having round orifice. The filaments extruded from the orifice were then cooled by blowing with a quenching gas of 16.1° C. at 0.44 meter/sec. velocity. After quenching, the filaments were treated with an aqueous liquidcontaining 10% oil by contacting an applicator located at a distance of 110 cm from the orifice so as to facilitate the solidifying of the hot filaments. The oil per unit of the treatment was 0.6%. The cooled and solidified filaments were then taken up by passing through a pair of driven take-up rolls at a speed of 3000 meter/minute. The obtained yarn bundles are 200 denier, and 24 filaments per yarn bundle. The strength (gram/denier) and the elongation (%) of the yarn bundles were first tested. The yarn bundles were then subjected to stretching and false twisting, and tested for their strength and elongation. The results are summarized in Table 1 below. TABLE 1 Before After stetching stetching Example (1) 103d Strength (g/d) Elongation (%) 68.21d Strength (g/d) Elongation (%) Regular Average 2.54 115.26 Average 4.69 36.88 rectangular Standard 0.27 13.94 Standard 0.15 4.06 derivation derivation variation 10.60  12.09 variation 3.25 11.0 Example (2) 197.93d Strength (g/d) Elongation (%) 135.08d Strength (g/d) Elongation (%) Regular Average 2.29 123.87 Average 3.79 39.60 rectangular Standard 0.15 10.69 Standard 0.18 5.16 derivation derivation variation 6.65 8.63 variation 4.75 13.03 Comparative example (1) 98.73d Strength (g/d) Elongation (%) 67.8d Strength (g/d) Elongation (%) Round Average 2.48 114.99 Average 4.57 40.81 Standard 0.12 6.07 Standard 0.09 2.30 derivation derivation variation 4.74 5.28 variation 1.97 5.64 Comparative example (2) 201d Strength (g/d) Elongation (%) 124.6d Strength (g/d) Elongation (%) Round Average 2.41 143.88 Average 4.49 38.44 Standard 0.13 10.00 Standard 0.19 3.08 derivation derivation variation 5.25 6.95 variation 4.18 8.01

EXAMPLE 3 The Preparation of Fibers Having Regular Triangular Cross-Section (2)

[0032] A melt dope containing R-PET (intrinsic viscosity=0.64) was prepared by melting the polymer at 280° C. The melt was then spun at 32.8 grams/minute through a spinneret having round orifice. The filaments extruded from the orifice were then cooled by blowing with a quenching air of 16.1° C. at 0.44 meter/sec. velocity. After quenching, the filaments were treated with an aqueous liquid containing 10% oil by contacting an applicator located at a distance of 110 cm from the orifice so as to facilitate the solidifying of the hot filaments. The oil per unit of the treatment was 0.6%. The cooled and solidified filaments were then taken up by passing through a pair of driven take-up rolls at a speed of 3000 meter/minute. The obtained yarn bundles are 100 denier, and 24 filaments per yarn bundle. The strength (gram/denier) and the elongation (%) of the yarn bundles were first tested. The yarn bundles were then subjected to stretching and false twisting. The cross-section of the resulting fiber is shown in FIG. 2.

[0033] The fibers obtained respectively from example 1 and comparative example 1 were woven into fabrics. Sample fabrics were prepared and the wind resistance coefficient (WRC) of the sample fabrics were tested. The test results are indicated Table 2 below. TABLE 2 flow rate (1/min) of WRC (comparative wind (mmH₂O) WRC (example) (mmH₂O) example 1) (mmH₂O) 10 3.4 2.1 20 6.8 4.9 40 10.5 10.7 60 18.4 18.3 80 30.5 22.4

[0034] As can be seen from Table 2, the wind resistance coefficient of the fabrics made by the fibers of the invention is about 15% higher than that of the fabrics made by conventional fibers which have a round cross-section.

[0035] The lightness (L) of the sample fabrics made by the fibers of example 1 and comparative example 1 were also tested. The tested data shows that the L value of sample fabrics of example 1 is 93.84 while the L value of the fabrics of comparative example 1 is 92.45. It is indicative from the data as shown above that the fibers of the present invention have almost the same mechanical characteristics as conventional fibers, but the windproof characteristics, brightness and heat insulation are superior to conventional fibers.

[0036] While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. 

What is claimed is:
 1. A method of fabricating a non-hollow fiber having regular polygonal cross-section, comprising the following steps: melting a thermoplastic polymer; extruding the melted polymer through a spinneret orifice having a regular polygonal cross-section to form molten filaments; and solidifying the molten filaments to form the non-hollow fiber having regular polygonal cross-section.
 2. The method as claimed in claim 1, further comprising the steps of stretching and false twisting the solidified filaments.
 3. The method as claimed in claim 1, wherein the fabricated fiber has a regular rectangular cross-section.
 4. The method as claimed in claim 1, wherein the fabricated fiber has a regular triangular cross-section.
 5. The method as claimed in claim 1, wherein the plastic polymer is selected from the group consisting of polyester, polyamide and polyolefin.
 6. The method as claimed in claim 5, wherein the polyester is poly(ethylene terephthalate).
 7. The method as claimed in claim 5, wherein the polyamide is Nylon 6 or Nylon
 66. 8. The method as claimed in claim 5, wherein the polyolef in is polypropylene.
 9. The method as claimed in claim 1, wherein the melting is performed at a temperature between 150-300° C.
 10. A non-hollow fiber having regular polygonal cross-section fabricated by the method as claimed in claim
 1. 11. The non-hollow fiber as claimed in claim 10, having a fineness of 0.5-5 d.p.f.
 12. A fabric made by the non-hollow fiber as claimed in claim
 10. 13. The fabric as claimed in claim 12 in the form of woven fabric, knitted fabric or non-woven fabric.
 14. The fabric as claimed in claim 13, having an lightness value (L) higher than 95 and the windproof coefficient is at least 15% higher than that of a fiber having a round cross-section. 